U.S. patent number 10,356,718 [Application Number 15/670,695] was granted by the patent office on 2019-07-16 for synchronization for extending battery life.
This patent grant is currently assigned to InterDigital Technology Corporation. The grantee listed for this patent is InterDigital Technology Corporation. Invention is credited to Steven Jeffrey Goldberg, Stephen E. Terry.
United States Patent |
10,356,718 |
Goldberg , et al. |
July 16, 2019 |
Synchronization for extending battery life
Abstract
The present invention discloses a method and system for
efficiently supporting data calls to WTRUs in systems that also
support telephony. Various types of data is transmitted on a known
schedule which is tightly synchronized to a predetermined time
frame. The WTRUs synchronize their wake-up periods to search for
data at times when data may or will actually be transmitted to
them.
Inventors: |
Goldberg; Steven Jeffrey
(Delray Beach, FL), Terry; Stephen E. (Northport, NY) |
Applicant: |
Name |
City |
State |
Country |
Type |
InterDigital Technology Corporation |
Wilmington |
DE |
US |
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Assignee: |
InterDigital Technology
Corporation (Wilmington, DE)
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Family
ID: |
29420451 |
Appl.
No.: |
15/670,695 |
Filed: |
August 7, 2017 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20170339637 A1 |
Nov 23, 2017 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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14104497 |
Dec 12, 2013 |
9730158 |
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13183627 |
Jan 7, 2014 |
8625545 |
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10428566 |
Sep 20, 2011 |
8023475 |
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60378901 |
May 6, 2002 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
52/0216 (20130101); H04W 52/0229 (20130101); H04W
56/001 (20130101); H04B 1/1615 (20130101); Y02D
30/70 (20200801); H04M 1/72522 (20130101); H04M
1/72519 (20130101) |
Current International
Class: |
H04J
3/06 (20060101); H04W 56/00 (20090101); H04B
1/16 (20060101); H04W 52/02 (20090101); H04M
1/725 (20060101) |
Field of
Search: |
;370/350,347,329,337
;455/458 |
References Cited
[Referenced By]
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May 2002 |
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WO |
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Other References
ANSI/IEEE Std 802.11, 1999 Edition, Information
technology--Telecommunications and information exchange between
systems--Local and metropolitan area networks--Specific
requirements--Part 11: Wireless LAN Medium Access Control (MAC) and
Physical Layer (PHY) Specifications, (Mar. 18, 1999). cited by
applicant .
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Radio Message System (ERMES); Part 4: Air interface specification,"
Jul. 1992, pp. 1-39. cited by applicant .
Holma et al., "WCDMA for UMTS: Radio Access for Third Generation
Mobile Communications," Revised Edition, Wiley, (Apr. 12, 2001).
cited by applicant .
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Air Interface for Fixed Broadband Wireless Access Systems, IEEE
Std. 802.16-2001 (Apr. 8, 2002). cited by applicant .
IEEE Std 802.16a-2003, IEEE Standard for Local and metropolitan
area networks, Part 16: Air Interface for Fixed Broadband Wireless
Access Systems--Amendment 2: Medium Access Control Modifications
and Additional Physical Layer Specifications for 2-11 GHz, (Apr. 1,
2003). cited by applicant .
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(2002). cited by applicant .
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3GPP TS 25.304 V3.12.0 (Dec. 2002). cited by applicant .
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Group Radio Access Network; UE Procedures in Idle Mode and
Procedures for Cell Reselection in Connected Mode (Release 4),"
3GPP TS 25.304 V4.4.0 (Mar. 2002). cited by applicant .
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Group Radio Access Network; UE Procedures in Idle Mode and
Procedures for Cell Reselection in Connected Mode (Release 4),"
3GPP TS 25.304 V4.6.0 (Dec. 2002). cited by applicant .
Third Generation Partnership Project, "Technical Specification
Group Radio Access Network; UE Procedures in Idle Mode and
Procedures for Cell Reselection in Connected Mode (Release 5),"
3GPP TS 25.304 V5.0.0 (Mar. 2002). cited by applicant .
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Group Radio Access Network; UE Procedures in Idle Mode and
Procedures for Cell Reselection in Connected Mode (Release 5),"
3GPP TS 25.304 V5.2.0 (Dec. 2002). cited by applicant .
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Cell Reselection in Connected Mode (Release 1999), 3GPP TS 25.304
V3.10.0 (Mar. 2002). cited by applicant.
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Primary Examiner: Le; Danh C
Attorney, Agent or Firm: Volpe and Koenig, P.C.
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser.
No. 14/104,497, filed Dec. 12, 2013, which is a continuation of
U.S. patent application Ser. No. 13/183,627, filed Jul. 15, 2011,
which issued as U.S. Pat. No. 8,625,545 on Jan. 7, 2014, which is a
continuation of U.S. patent application Ser. No. 10/428,566, filed
May 2, 2003, which issued as U.S. Pat. No. 8,023,475 on Sep. 20,
2011, which claims priority from U.S. Provisional Application No.
60/378,901, filed on May 6, 2002, the contents of which are hereby
incorporated by reference herein.
Claims
What is claimed is:
1. A wireless transmit/receive unit (WTRU) comprising: a receiver
configured to receive scheduling information on a broadcast control
channel (BCCH) indicating transmission time intervals to monitor
for downlink shared channel transmissions of broadcast data,
wherein each transmission time interval is at least one time slot
in duration; the receiver further configured to monitor the
transmission time intervals; the receiver further configured to
receive broadcast data in downlink shared channel transmissions
during the monitored transmission time intervals based on the
scheduling information; and the receiver further configured to
receive synchronization information prior to the scheduling
information, wherein the scheduling information is received at one
or more fixed intervals.
2. The WTRU of claim 1, wherein the receiver enters a reduced power
state between the monitored transmission time intervals.
3. The WTRU of claim 2, wherein the reduced power state includes
operating radio frequency (RF) reception circuitry of the WTRU in a
reduced power mode.
4. The WTRU of claim 1, wherein the scheduling information is
received from a base station.
5. The WTRU of claim 1, further comprising: a transmitter
configured to transmit a request for one or more messages, wherein
an availability of the one or more messages is indicated via the
broadcast control channel.
6. A method for use in a wireless transmit/receive unit (WTRU), the
method comprising: receiving scheduling information on a broadcast
control channel (BCCH) indicating transmission time intervals to
monitor for downlink shared channel transmissions of broadcast
data, wherein each transmission time interval is at least one time
slot in duration; monitoring the transmission time intervals;
receiving broadcast data in downlink shared channel transmissions
during the monitored transmission time intervals based on the
scheduling information; and receiving synchronization information
prior to the scheduling information, wherein the scheduling
information is received at one or more fixed intervals.
7. The method of claim 6, wherein the receiver enters a reduced
power state between the monitored transmission time intervals.
8. The method of claim 7, wherein the reduced power state includes
operating radio frequency (RF) reception circuitry of the WTRU in a
reduced power mode.
9. The method of claim 6, wherein the scheduling information is
received from a base station.
10. The method of claim 6, further comprising: transmitting a
request for one or more messages, wherein an availability of the
one or more messages is indicated via the broadcast control
channel.
11. A method for use in a base station, the method comprising:
transmitting scheduling information on a broadcast control channel
(BCCH) indicating transmission time intervals to monitor for
downlink shared channel transmissions of broadcast data, wherein
each transmission time interval is at least one time slot in
duration; transmitting broadcast data in downlink shared channel
transmissions during the monitored transmission time intervals
based on the scheduling information; and transmitting
synchronization information prior to the scheduling information,
wherein the scheduling information is transmitted at one or more
fixed intervals.
12. The method of claim 11, wherein the scheduling information is
transmitted to a wireless transmit/receive unit (WTRU).
13. The method of claim 12, wherein the WTRU enters a reduced power
state between the monitored transmission time intervals.
14. The method of claim 13, wherein the reduced power state
includes operating radio frequency (RF) reception circuitry of the
WTRU in a reduced power mode.
15. The WTRU of claim 1, wherein receipt of the broadcast data is
unacknowledged by the WTRU.
16. The method of claim 6, wherein receipt of the broadcast data is
unacknowledged by the WTRU.
17. The method of claim 11, wherein receipt of the broadcast data
is unacknowledged.
18. The method of claim 11, further comprising: receiving a request
for one or more messages, wherein an availability of the one or
more messages is indicated via the broadcast control channel.
Description
FIELD OF INVENTION
The present invention relates to the field of wireless
communications. More specifically, the present invention relates to
the optimization of power resources of wireless devices within
wireless communications systems.
BACKGROUND
The more often a battery operated device, such as a wireless
transmit/receive unit (WTRU), looks for possible data being sent to
it, the more power the device consumes. In networks and devices
that support not only telephony, but also data transmission, the
manner in which the devices look for messages from the network
varies, depending on whether the device is looking for incoming
phone calls or incoming data transmissions.
With respect to telephony, users are accustomed to terrestrial
networks wherein a ringing sound is heard almost immediately after
a particular telephone number is dialed. To meet this expectation
in wireless environments, a WTRU must frequently scan the network
to minimize the delay in establishing a connection as perceived by
a person placing a phone call. That is, the WTRU must frequently
scan the network for incoming calls to minimize the time between
when the network sends a calling signal or message and when the
receiving WTRU actually checks for the calling signal.
This arrangement is quite suitable for telephony, but is
inefficient for data transmission. With respect to data
transmission, the strict requirements necessary for ensuring a
near-instantaneous response to a call are not required. Longer
delays are generally tolerated when transmitting data to WTRUs such
as pagers and similar devices, for example. However, it is
generally expected, that such devices respond to a message
indicating that there is an incoming data transmission "in real
time." Therefore, the network must also be scanned rather
frequently in some cases when dealing with data transmission, but
even in such situations the frequency with which the network must
be scanned is less then when dealing with telephony.
The amount of delay that is acceptable varies according to the type
of data being transmitted and user preference. For example, longer
delays are tolerated where information is infrequently updated,
such as traffic or weather data. In the case of a pager, a
reasonable response time could be evaluated in terms of an
anticipated time delay for the user to respond to a paged message.
In the case of multiple network transmissions (i.e. stock quotes,
sport scores, etc.), some users want information occasionally
updated so that they may have longer battery life. Other users have
less concern for battery life and simply want data updated rapidly.
Examples of users wishing frequent updates would be people desiring
immediate information updates and people whose WTRU is connected to
an external power supply. In the case of stock quotes, for example,
there are casual watchers, and those who desire immediate
notification of changes. Thus, if the user would expect to respond
to a message quickly, the response time should ideally be fairly
quick, but still much greater than the necessary response time for
a WTRU becoming aware of an incoming telephone call.
It would therefore be desirable to have a method and system for
efficiently supporting data transmissions as well as telephony.
SUMMARY
A wireless network permits WTRUs to operate in a quiescent mode of
operation according to a synchronization schedule. Synchronization
information is provided to the WTRUs to inform them of when they
may be in a quiescent mode and when they need to wake up and
retrieve data.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is diagram showing a wireless communication network.
FIG. 2 is a data diagram showing a frame structure used in an
embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
According to the present invention, synchronization information is
provided to wireless transmit/receive units (WTRUs) to inform them
of when they may be in a quiescent mode (i.e. when they may be
asleep) and when they need to wake up and retrieve data. For
purposes of describing the invention, a WTRU may have a
transmit-only, a receive-only or a transmit-and-receive capability.
That is, a WTRU may be any type of device capable of receiving
and/or transmitting data in a wireless environment.
Referring now to FIG. 1, a representation of a network is shown
wherein one or more base stations 21 communicate with a plurality
of WTRUs, such as WTRU 22 which will be referred to when describing
the invention. The WTRU 22, as explained, can be any of a number of
devices supported by the network. Examples include user equipment
(UE), cellphone, pager, Blackberry.TM. device, computer with a
modem connection or any other device that is capable of operating
in a wireless environment. The base station 21 is controlled by a
radio network controller (RNC) 25 which performs various network
supervisory and communications functions. The base station 21
includes signal processing circuitry 31 and an RF stage 32, which
includes a transmit function. Signals from the base station 21 are
transmitted to the WTRUs within its cell or transmission area, as
represented by antennas 33, 34. The WTRU 22 has an RF stage 37 and
a signal processing stage 38. A receive function is provided by the
WTRU's RF stage 37 in order to receive signals transmitted by the
base station 21. In the case of two-way devices, the RF stages 32
and 37 have both transmit and receive functions, permitting the
WTRU 22 to transmit data in an uplink and receive data in a
downlink. While transmitting requires significantly greater power
than receiving, issues of quiescent operation primarily affect the
downlink, so the receiver function of the WTRU 22 is
significant.
In accordance with the present invention, the WTRU 22 uses its
signal processing circuitry 38 in order to control when the RF
stage 37 is receiving signals from the base station 21. This allows
the operation of the receive function of the WTRU 22 to be active
primarily during times when signals are expected to include data
intended for that particular WTRU 22. During at least some of the
time when signals are not intended for that particular WTRU 22, the
WTRU goes quiescent, meaning that most reception and signal
processing by the WTRU 22 is turned off.
Regardless of the manner in which data is being transmitted from
the network, the WTRUs are preferably synchronized so that they may
wake up and go sleep to maximize battery life and satisfy user
preferences. The synchronization information provided to the WTRUs
is provided in accordance with the manner in which data is being
delivered from the network. That is, regardless of the manner in
which data is being transmitted from the network, synchronization
information is provided to WTRUs so that they are aware of when
they need to be awake and when they may go to sleep.
As known to those skilled in the art, data may be provided from the
network to WTRUs in a variety of ways, as desired. In one
embodiment, data may be transmitted in the form of scheduled
transmissions. In this case, the network transmits various types of
broadcast or multicast data on a known schedule that is tightly
synchronized to a time frame known by both the transmitting WTRU
and the receiving WTRU(s). The WTRUs can then synchronize their
wake-ups to search occurrences when data may or will be
transmitted. To implement this embodiment in 3.sup.rd generation
cellular networks, scheduling information can either be provided by
a common control channel such as the Broadcast Common Control
Channel (BCCH) signaling or a Dedicated Control Channel (DCCH)
signaling. Where BCCH signaling is used, scheduling (i.e.
synchronization) information may be signaled for all broadcast and
multicast services. If DCCH signaling is used, only scheduling of
services that are specific to a receiving WTRU will be
signaled.
In another embodiment, data may be transmitted in the form of
multiple network transmissions. That is, as mentioned, some users
want information updated only occasionally in favor of longer
battery life whereas others want data updated rapidly without
regard for battery life. Therefore, in this embodiment, data is
transmitted (even where there is no data change) at a rate that is
consistent with a user's preference for the frequency of updates
versus battery life. By transmitting data at a rapid by
synchronized pace (i.e. the highest available rate desired by a
user) and repeating the transmissions even when there is no data
change, individual receiving WTRUs can wake up and search for data
at different time intervals, according to user preference. This
satisfies the needs of both groups of users (as well as those in
between) by providing an adjustable degree of settings.
Since the amount of delay that is acceptable varies according to
the particular user application, it is likely that any tradeoff
between delay and power consumption would have different optimums
for different users. Therefore latency (i.e. delay time) may be
optimized based on usage, as low latency conflicts with low power
consumption. This becomes particularly significant during times
when the WTRU is not in active use.
To implement this embodiment in 3.sup.rd generation cellular
networks, once a receiving WTRU is aware of scheduled broadcast or
multicast transmissions, the receiving WTRU can then acquire the
service (i.e. the scheduled broadcast or multicast transmissions)
transmitted on either the Forward Access Channel (FACH) or the
Downlink Shared Channel (DSCH) on an as needed basis. The network
will transmit the broadcast or multicast data in either Radio Link
Control Transparent or Unacknowledged Mode, which allows the
receiving WTRU to determine if reception is needed autonomously
without requiring interaction or causing errors to be perceived in
the network.
A modification to the embodiment where multiple network
transmissions are provided is to transmit only until certain WTRUs
in the network's range acknowledge receipt. This modification has
the advantage of terminating the transmission when it is no longer
necessary while also providing some robustness to the transmission
of the information for appropriately enabled devices. This
modification has the disadvantage of requiring uplink transmissions
from WTRUs and may not be suitable for a large number of WTRUs.
With respect to implementation in 3.sup.rd generation cellular
networks, there are several network acknowledgement alternatives.
For example, where there is a single receiving WTRU, Radio Link
Control Acknowledged mode provides an automatic repeat request
mechanism for assured delivery. When there are multiple receiving
WTRUs, layer 3 acknowledgements can either by provided by Radio
Resource Control signaling within the Access Stratum, or by
transparent data transfer of Non Access Stratum signaling.
In another embodiment, the network simply transmits the fact that
there is a message awaiting delivery. That is, rather then sending
the message all the time, in some instances it is more efficient to
just notify the WTRUs that a message for them exists. In 3.sup.rd
generation cellular networks the availability of the message is
identified by a common control channel, such as the BCCH. Those
WTRUs that want the message will then request its transmission from
the network. The request for the message may either be for the
particular message or registration with the multicast service for
reception of one or more messages associated with that service.
This approach is suitable when only a small number of WTRUs are
expected to request the actual message, while many WTRUs may want
the actual ability to do so. This situation may arise, for example,
where there is only limited information in the initial transmission
informing WTRUs of a message's existence. In 3.sup.rd generation
cellular networks, the receiving WTRU will generate a request for
the service with either layer Access Stratum or Non Access Stratum
signaling. The network will then either signal broadcast scheduling
information or establish a dedicated radio bearer for transmission
of the service. That is, the network with knowledge of the number
of WTRUs requesting the message or service of multiple messages
determines the most efficient method of transmission. If there is a
large number of recipients, scheduling of information will be
signaled on a common control channel. This information will
identify a common channel such as the FACH or DSCH, and the time of
transmission for reception of the service. If there is a small
number of WTRUs requesting the message or service a dedicated
channel will be established to each requesting or registered WTRU
associated with this message or service.
Referring now to FIG. 2, a signal frame diagram including a
sequence of transmissions transmitted by a base station to multiple
WTRUs is shown. As mentioned, the delivery of transmissions is
synchronized so that messages directed to a particular WTRU or
group of WTRUs associated with that message or service is delivered
when that particular WTRU or group of WTRUs associated with that
message or service is awake looking for data. To accomplish this,
in one embodiment, the transmissions are divided into frames 54
wherein seventy two (72) frames 54 make up a superframe, as shown
in FIG. 2. For simplicity in describing the invention, portions of
two superframes 51, 52 are shown. It should be noted, however, that
superframes 51, 52 are part of a repeating series of superframes,
each having seventy two (72) frames. It should also be noted that a
superframe having 72 frames is provided purely by way of example,
as other multiframe sequences are possible.
The frames 54 are divided into time slots 56, as shown in an
expanded view 71E of frame 71. The time slots 56 within each frame,
such as frame 71, include transmission packets designated, for
example, zero (0) through (14). Each time slot 56 may include data
intended for one or more devices. By way of example, slot 6
includes data for WTRU 101 and slot 12 includes data for WTRUs 102
and 103.
WTRUs 101 through 103 preferably synchronize their reception so
that they are able to receive data during their respective
allocated time period. The use of fixed time periods for data
reception means that, once a WTRU is provided with its
synchronization information (i.e. information related to the
particular time sequence of signals intended for that WTRU), the
WTRU may synchronize with that time sequence and remain asleep
(i.e. quiescent) for a portion of a superframe. This results in
reduced power consumption because a WTRU in a quiescent state has
most or all of its RF reception circuits turned off. The WTRU,
preferably, has most of its signal processing circuits turned off
as well. In this embodiment, the reduction in power consumption
approximately corresponds to the number of frames that are
ignored.
Once synchronized, WTRUs 101 through 103 wake up only in their
respective slot, radio frame or multiframe associated with the
particular interleaving period known as the transmission time
interval (TTI). From the network perspective, for each superframe,
the network will wait for frame 71, slot 6 before transmitting data
to WTRU 101.
It should be noted that WTRUs may wake up at other times (i.e.
other than their designated slots), if needed. For example, it may
be necessary to wake up for certain common signals. Additionally,
the network and WTRUs may be adapted so that a special "wake up"
signal is transmitted from the network to a particular WTRU or
group of WTRUs where it is necessary for the WTRU(s) to wake up and
receive data outside of their designated slot.
It should be noted that the division of transmissions into
superframes, frames, and slots may be varied as desired. For
example, in the discussion above, it is assumed that a WTRU will
wake up at least every superframe and look for data in at least one
slot of at least one frame. However, as mentioned, data
transmissions may be provided to users as desired so as to satisfy
user preferences for battery life and frequency of data renewal.
Therefore, the timing of a particular synchronization scheme may
similarly be varied. By way of example, it is possible to create a
synchronization schedule between network data delivery and a WTRU's
receipt thereof wherein more than one superframe passes between
WTRU wake up periods within which a WTRU wakes up and looks for a
message at its assigned frame and slot.
While the present invention has been described in terms of the
preferred embodiment, other variations which are within the scope
of the invention as outlined in the claims below will be apparent
to those skilled in the art.
* * * * *